drivers/gpu/vga/vga_switcheroo.c

   1 /*
   2  * Copyright (c) 2010 Red Hat Inc.
   3  * Author : Dave Airlie <airlied@redhat.com>
   4  *
   5  *
   6  * Licensed under GPLv2
   7  *
   8  * vga_switcheroo.c - Support for laptop with dual GPU using one set of outputs
   9
  10  Switcher interface - methods require for ATPX and DCM
  11  - switchto - this throws the output MUX switch
  12  - discrete_set_power - sets the power state for the discrete card
  13
  14  GPU driver interface
  15  - set_gpu_state - this should do the equiv of s/r for the card
  16                   - this should *not* set the discrete power state
  17  - switch_check  - check if the device is in a position to switch now
  18  */
  19
  20 #include <linux/module.h>
  21 #include <linux/dmi.h>
  22 #include <linux/seq_file.h>
  23 #include <linux/uaccess.h>
  24 #include <linux/fs.h>
  25 #include <linux/debugfs.h>
  26 #include <linux/fb.h>
  27
  28 #include <linux/pci.h>
  29 #include <linux/vga_switcheroo.h>
  30
  31 #include <linux/vgaarb.h>
  32
  33 struct vga_switcheroo_client {
  34         struct pci_dev *pdev;
  35         struct fb_info *fb_info;
  36         int pwr_state;
  37         const struct vga_switcheroo_client_ops *ops;
  38         int id;
  39         bool active;
  40         struct list_head list;
  41 };
  42
  43 static DEFINE_MUTEX(vgasr_mutex);
  44
  45 struct vgasr_priv {
  46
  47         bool active;
  48         bool delayed_switch_active;
  49         enum vga_switcheroo_client_id delayed_client_id;
  50
  51         struct dentry *debugfs_root;
  52         struct dentry *switch_file;
  53
  54         int registered_clients;
  55         struct list_head clients;
  56
  57         struct vga_switcheroo_handler *handler;
  58 };
  59
  60 #define ID_BIT_AUDIO            0x100
  61 #define client_is_audio(c)      ((c)->id & ID_BIT_AUDIO)
  62 #define client_is_vga(c)        ((c)->id == -1 || !client_is_audio(c))
  63 #define client_id(c)            ((c)->id & ~ID_BIT_AUDIO)
  64
  65 static int vga_switcheroo_debugfs_init(struct vgasr_priv *priv);
  66 static void vga_switcheroo_debugfs_fini(struct vgasr_priv *priv);
  67
  68 /* only one switcheroo per system */
  69 static struct vgasr_priv vgasr_priv = {
  70         .clients = LIST_HEAD_INIT(vgasr_priv.clients),
  71 };
  72
  73 int vga_switcheroo_register_handler(struct vga_switcheroo_handler *handler)
  74 {
  75         mutex_lock(&vgasr_mutex);
  76         if (vgasr_priv.handler) {
  77                 mutex_unlock(&vgasr_mutex);
  78                 return -EINVAL;
  79         }
  80
  81         vgasr_priv.handler = handler;
  82         mutex_unlock(&vgasr_mutex);
  83         return 0;
  84 }
  85 EXPORT_SYMBOL(vga_switcheroo_register_handler);
  86
  87 void vga_switcheroo_unregister_handler(void)
  88 {
  89         mutex_lock(&vgasr_mutex);
  90         vgasr_priv.handler = NULL;
  91         mutex_unlock(&vgasr_mutex);
  92 }
  93 EXPORT_SYMBOL(vga_switcheroo_unregister_handler);
  94
  95 static void vga_switcheroo_enable(void)
  96 {
  97         int ret;
  98         struct vga_switcheroo_client *client;
  99
 100         /* call the handler to init */
 101         vgasr_priv.handler->init();
 102
 103         list_for_each_entry(client, &vgasr_priv.clients, list) {
 104                 if (client->id != -1)
 105                         continue;
 106                 ret = vgasr_priv.handler->get_client_id(client->pdev);
 107                 if (ret < 0)
 108                         return;
 109
 110                 client->id = ret;
 111         }
 112         vga_switcheroo_debugfs_init(&vgasr_priv);
 113         vgasr_priv.active = true;
 114 }
 115
 116 static int register_client(struct pci_dev *pdev,
 117                            const struct vga_switcheroo_client_ops *ops,
 118                            int id, bool active)
 119 {
 120         struct vga_switcheroo_client *client;
 121
 122         client = kzalloc(sizeof(*client), GFP_KERNEL);
 123         if (!client)
 124                 return -ENOMEM;
 125
 126         client->pwr_state = VGA_SWITCHEROO_ON;
 127         client->pdev = pdev;
 128         client->ops = ops;
 129         client->id = id;
 130         client->active = active;
 131
 132         mutex_lock(&vgasr_mutex);
 133         list_add_tail(&client->list, &vgasr_priv.clients);
 134         if (client_is_vga(client))
 135                 vgasr_priv.registered_clients++;
 136
 137         /* if we get two clients + handler */
 138         if (!vgasr_priv.active &&
 139             vgasr_priv.registered_clients == 2 && vgasr_priv.handler) {
 140                 printk(KERN_INFO "vga_switcheroo: enabled\n");
 141                 vga_switcheroo_enable();
 142         }
 143         mutex_unlock(&vgasr_mutex);
 144         return 0;
 145 }
 146
 147 int vga_switcheroo_register_client(struct pci_dev *pdev,
 148                                    const struct vga_switcheroo_client_ops *ops)
 149 {
 150         return register_client(pdev, ops, -1,
 151                                pdev == vga_default_device());
 152 }
 153 EXPORT_SYMBOL(vga_switcheroo_register_client);
 154
 155 int vga_switcheroo_register_audio_client(struct pci_dev *pdev,
 156                                          const struct vga_switcheroo_client_ops *ops,
 157                                          int id, bool active)
 158 {
 159         return register_client(pdev, ops, id | ID_BIT_AUDIO, active);
 160 }
 161 EXPORT_SYMBOL(vga_switcheroo_register_audio_client);
 162
 163 static struct vga_switcheroo_client *
 164 find_client_from_pci(struct list_head *head, struct pci_dev *pdev)
 165 {
 166         struct vga_switcheroo_client *client;
 167         list_for_each_entry(client, head, list)
 168                 if (client->pdev == pdev)
 169                         return client;
 170         return NULL;
 171 }
 172
 173 static struct vga_switcheroo_client *
 174 find_client_from_id(struct list_head *head, int client_id)
 175 {
 176         struct vga_switcheroo_client *client;
 177         list_for_each_entry(client, head, list)
 178                 if (client->id == client_id)
 179                         return client;
 180         return NULL;
 181 }
 182
 183 static struct vga_switcheroo_client *
 184 find_active_client(struct list_head *head)
 185 {
 186         struct vga_switcheroo_client *client;
 187         list_for_each_entry(client, head, list)
 188                 if (client->active && client_is_vga(client))
 189                         return client;
 190         return NULL;
 191 }
 192
 193 int vga_switcheroo_get_client_state(struct pci_dev *pdev)
 194 {
 195         struct vga_switcheroo_client *client;
 196
 197         client = find_client_from_pci(&vgasr_priv.clients, pdev);
 198         if (!client)
 199                 return VGA_SWITCHEROO_NOT_FOUND;
 200         if (!vgasr_priv.active)
 201                 return VGA_SWITCHEROO_INIT;
 202         return client->pwr_state;
 203 }
 204 EXPORT_SYMBOL(vga_switcheroo_get_client_state);
 205
 206 void vga_switcheroo_unregister_client(struct pci_dev *pdev)
 207 {
 208         struct vga_switcheroo_client *client;
 209
 210         mutex_lock(&vgasr_mutex);
 211         client = find_client_from_pci(&vgasr_priv.clients, pdev);
 212         if (client) {
 213                 if (client_is_vga(client))
 214                         vgasr_priv.registered_clients--;
 215                 list_del(&client->list);
 216                 kfree(client);
 217         }
 218         if (vgasr_priv.active && vgasr_priv.registered_clients < 2) {
 219                 printk(KERN_INFO "vga_switcheroo: disabled\n");
 220                 vga_switcheroo_debugfs_fini(&vgasr_priv);
 221                 vgasr_priv.active = false;
 222         }
 223         mutex_unlock(&vgasr_mutex);
 224 }
 225 EXPORT_SYMBOL(vga_switcheroo_unregister_client);
 226
 227 void vga_switcheroo_client_fb_set(struct pci_dev *pdev,
 228                                  struct fb_info *info)
 229 {
 230         struct vga_switcheroo_client *client;
 231
 232         mutex_lock(&vgasr_mutex);
 233         client = find_client_from_pci(&vgasr_priv.clients, pdev);
 234         if (client)
 235                 client->fb_info = info;
 236         mutex_unlock(&vgasr_mutex);
 237 }
 238 EXPORT_SYMBOL(vga_switcheroo_client_fb_set);
 239
 240 static int vga_switcheroo_show(struct seq_file *m, void *v)
 241 {
 242         struct vga_switcheroo_client *client;
 243         int i = 0;
 244         mutex_lock(&vgasr_mutex);
 245         list_for_each_entry(client, &vgasr_priv.clients, list) {
 246                 seq_printf(m, "%d:%s%s:%c:%s:%s\n", i,
 247                            client_id(client) == VGA_SWITCHEROO_DIS ? "DIS" : "IGD",
 248                            client_is_vga(client) ? "" : "-Audio",
 249                            client->active ? '+' : ' ',
 250                            client->pwr_state ? "Pwr" : "Off",
 251                            pci_name(client->pdev));
 252                 i++;
 253         }
 254         mutex_unlock(&vgasr_mutex);
 255         return 0;
 256 }
 257
 258 static int vga_switcheroo_debugfs_open(struct inode *inode, struct file *file)
 259 {
 260         return single_open(file, vga_switcheroo_show, NULL);
 261 }
 262
 263 static int vga_switchon(struct vga_switcheroo_client *client)
 264 {
 265         if (vgasr_priv.handler->power_state)
 266                 vgasr_priv.handler->power_state(client->id, VGA_SWITCHEROO_ON);
 267         /* call the driver callback to turn on device */
 268         client->ops->set_gpu_state(client->pdev, VGA_SWITCHEROO_ON);
 269         client->pwr_state = VGA_SWITCHEROO_ON;
 270         return 0;
 271 }
 272
 273 static int vga_switchoff(struct vga_switcheroo_client *client)
 274 {
 275         /* call the driver callback to turn off device */
 276         client->ops->set_gpu_state(client->pdev, VGA_SWITCHEROO_OFF);
 277         if (vgasr_priv.handler->power_state)
 278                 vgasr_priv.handler->power_state(client->id, VGA_SWITCHEROO_OFF);
 279         client->pwr_state = VGA_SWITCHEROO_OFF;
 280         return 0;
 281 }
 282
 283 static void set_audio_state(int id, int state)
 284 {
 285         struct vga_switcheroo_client *client;
 286
 287         client = find_client_from_id(&vgasr_priv.clients, id | ID_BIT_AUDIO);
 288         if (client && client->pwr_state != state) {
 289                 client->ops->set_gpu_state(client->pdev, state);
 290                 client->pwr_state = state;
 291         }
 292 }
 293
 294 /* stage one happens before delay */
 295 static int vga_switchto_stage1(struct vga_switcheroo_client *new_client)
 296 {
 297         struct vga_switcheroo_client *active;
 298
 299         active = find_active_client(&vgasr_priv.clients);
 300         if (!active)
 301                 return 0;
 302
 303         if (new_client->pwr_state == VGA_SWITCHEROO_OFF)
 304                 vga_switchon(new_client);
 305
 306         vga_set_default_device(new_client->pdev);
 307         return 0;
 308 }
 309
 310 /* post delay */
 311 static int vga_switchto_stage2(struct vga_switcheroo_client *new_client)
 312 {
 313         int ret;
 314         struct vga_switcheroo_client *active;
 315
 316         active = find_active_client(&vgasr_priv.clients);
 317         if (!active)
 318                 return 0;
 319
 320         active->active = false;
 321
 322         set_audio_state(active->id, VGA_SWITCHEROO_OFF);
 323
 324         if (new_client->fb_info) {
 325                 struct fb_event event;
 326                 event.info = new_client->fb_info;
 327                 fb_notifier_call_chain(FB_EVENT_REMAP_ALL_CONSOLE, &event);
 328         }
 329
 330         ret = vgasr_priv.handler->switchto(new_client->id);
 331         if (ret)
 332                 return ret;
 333
 334         if (new_client->ops->reprobe)
 335                 new_client->ops->reprobe(new_client->pdev);
 336
 337         if (active->pwr_state == VGA_SWITCHEROO_ON)
 338                 vga_switchoff(active);
 339
 340         set_audio_state(new_client->id, VGA_SWITCHEROO_ON);
 341
 342         new_client->active = true;
 343         return 0;
 344 }
 345
 346 static bool check_can_switch(void)
 347 {
 348         struct vga_switcheroo_client *client;
 349
 350         list_for_each_entry(client, &vgasr_priv.clients, list) {
 351                 if (!client->ops->can_switch(client->pdev)) {
 352                         printk(KERN_ERR "vga_switcheroo: client %x refused switch\n", client->id);
 353                         return false;
 354                 }
 355         }
 356         return true;
 357 }
 358
 359 static ssize_t
 360 vga_switcheroo_debugfs_write(struct file *filp, const char __user *ubuf,
 361                              size_t cnt, loff_t *ppos)
 362 {
 363         char usercmd[64];
 364         const char *pdev_name;
 365         int ret;
 366         bool delay = false, can_switch;
 367         bool just_mux = false;
 368         int client_id = -1;
 369         struct vga_switcheroo_client *client = NULL;
 370
 371         if (cnt > 63)
 372                 cnt = 63;
 373
 374         if (copy_from_user(usercmd, ubuf, cnt))
 375                 return -EFAULT;
 376
 377         mutex_lock(&vgasr_mutex);
 378
 379         if (!vgasr_priv.active) {
 380                 cnt = -EINVAL;
 381                 goto out;
 382         }
 383
 384         /* pwr off the device not in use */
 385         if (strncmp(usercmd, "OFF", 3) == 0) {
 386                 list_for_each_entry(client, &vgasr_priv.clients, list) {
 387                         if (client->active || client_is_audio(client))
 388                                 continue;
 389                         set_audio_state(client->id, VGA_SWITCHEROO_OFF);
 390                         if (client->pwr_state == VGA_SWITCHEROO_ON)
 391                                 vga_switchoff(client);
 392                 }
 393                 goto out;
 394         }
 395         /* pwr on the device not in use */
 396         if (strncmp(usercmd, "ON", 2) == 0) {
 397                 list_for_each_entry(client, &vgasr_priv.clients, list) {
 398                         if (client->active || client_is_audio(client))
 399                                 continue;
 400                         if (client->pwr_state == VGA_SWITCHEROO_OFF)
 401                                 vga_switchon(client);
 402                         set_audio_state(client->id, VGA_SWITCHEROO_ON);
 403                 }
 404                 goto out;
 405         }
 406
 407         /* request a delayed switch - test can we switch now */
 408         if (strncmp(usercmd, "DIGD", 4) == 0) {
 409                 client_id = VGA_SWITCHEROO_IGD;
 410                 delay = true;
 411         }
 412
 413         if (strncmp(usercmd, "DDIS", 4) == 0) {
 414                 client_id = VGA_SWITCHEROO_DIS;
 415                 delay = true;
 416         }
 417
 418         if (strncmp(usercmd, "IGD", 3) == 0)
 419                 client_id = VGA_SWITCHEROO_IGD;
 420
 421         if (strncmp(usercmd, "DIS", 3) == 0)
 422                 client_id = VGA_SWITCHEROO_DIS;
 423
 424         if (strncmp(usercmd, "MIGD", 4) == 0) {
 425                 just_mux = true;
 426                 client_id = VGA_SWITCHEROO_IGD;
 427         }
 428         if (strncmp(usercmd, "MDIS", 4) == 0) {
 429                 just_mux = true;
 430                 client_id = VGA_SWITCHEROO_DIS;
 431         }
 432
 433         if (client_id == -1)
 434                 goto out;
 435         client = find_client_from_id(&vgasr_priv.clients, client_id);
 436         if (!client)
 437                 goto out;
 438
 439         vgasr_priv.delayed_switch_active = false;
 440
 441         if (just_mux) {
 442                 ret = vgasr_priv.handler->switchto(client_id);
 443                 goto out;
 444         }
 445
 446         if (client->active)
 447                 goto out;
 448
 449         /* okay we want a switch - test if devices are willing to switch */
 450         can_switch = check_can_switch();
 451
 452         if (can_switch == false && delay == false)
 453                 goto out;
 454
 455         if (can_switch) {
 456                 pdev_name = pci_name(client->pdev);
 457                 ret = vga_switchto_stage1(client);
 458                 if (ret)
 459                         printk(KERN_ERR "vga_switcheroo: switching failed stage 1 %d\n", ret);
 460
 461                 ret = vga_switchto_stage2(client);
 462                 if (ret)
 463                         printk(KERN_ERR "vga_switcheroo: switching failed stage 2 %d\n", ret);
 464
 465         } else {
 466                 printk(KERN_INFO "vga_switcheroo: setting delayed switch to client %d\n", client->id);
 467                 vgasr_priv.delayed_switch_active = true;
 468                 vgasr_priv.delayed_client_id = client_id;
 469
 470                 ret = vga_switchto_stage1(client);
 471                 if (ret)
 472                         printk(KERN_ERR "vga_switcheroo: delayed switching stage 1 failed %d\n", ret);
 473         }
 474
 475 out:
 476         mutex_unlock(&vgasr_mutex);
 477         return cnt;
 478 }
 479
 480 static const struct file_operations vga_switcheroo_debugfs_fops = {
 481         .owner = THIS_MODULE,
 482         .open = vga_switcheroo_debugfs_open,
 483         .write = vga_switcheroo_debugfs_write,
 484         .read = seq_read,
 485         .llseek = seq_lseek,
 486         .release = single_release,
 487 };
 488
 489 static void vga_switcheroo_debugfs_fini(struct vgasr_priv *priv)
 490 {
 491         if (priv->switch_file) {
 492                 debugfs_remove(priv->switch_file);
 493                 priv->switch_file = NULL;
 494         }
 495         if (priv->debugfs_root) {
 496                 debugfs_remove(priv->debugfs_root);
 497                 priv->debugfs_root = NULL;
 498         }
 499 }
 500
 501 static int vga_switcheroo_debugfs_init(struct vgasr_priv *priv)
 502 {
 503         /* already initialised */
 504         if (priv->debugfs_root)
 505                 return 0;
 506         priv->debugfs_root = debugfs_create_dir("vgaswitcheroo", NULL);
 507
 508         if (!priv->debugfs_root) {
 509                 printk(KERN_ERR "vga_switcheroo: Cannot create /sys/kernel/debug/vgaswitcheroo\n");
 510                 goto fail;
 511         }
 512
 513         priv->switch_file = debugfs_create_file("switch", 0644,
 514                                                 priv->debugfs_root, NULL, &vga_switcheroo_debugfs_fops);
 515         if (!priv->switch_file) {
 516                 printk(KERN_ERR "vga_switcheroo: cannot create /sys/kernel/debug/vgaswitcheroo/switch\n");
 517                 goto fail;
 518         }
 519         return 0;
 520 fail:
 521         vga_switcheroo_debugfs_fini(priv);
 522         return -1;
 523 }
 524
 525 int vga_switcheroo_process_delayed_switch(void)
 526 {
 527         struct vga_switcheroo_client *client;
 528         const char *pdev_name;
 529         int ret;
 530         int err = -EINVAL;
 531
 532         mutex_lock(&vgasr_mutex);
 533         if (!vgasr_priv.delayed_switch_active)
 534                 goto err;
 535
 536         printk(KERN_INFO "vga_switcheroo: processing delayed switch to %d\n", vgasr_priv.delayed_client_id);
 537
 538         client = find_client_from_id(&vgasr_priv.clients,
 539                                      vgasr_priv.delayed_client_id);
 540         if (!client || !check_can_switch())
 541                 goto err;
 542
 543         pdev_name = pci_name(client->pdev);
 544         ret = vga_switchto_stage2(client);
 545         if (ret)
 546                 printk(KERN_ERR "vga_switcheroo: delayed switching failed stage 2 %d\n", ret);
 547
 548         vgasr_priv.delayed_switch_active = false;
 549         err = 0;
 550 err:
 551         mutex_unlock(&vgasr_mutex);
 552         return err;
 553 }
 554 EXPORT_SYMBOL(vga_switcheroo_process_delayed_switch);
 555